The present invention relates to an automated cleaning device for beverage drafting and dispensing systems, particularly for beer tapping systems in bars and restaurants. More specifically, the present invention provides a sliding valve with cuboid housing equipped with connecting sleeves to a tap line leading to a tapping cock, to a tap line leading to a keg or barrel and to a pressurized water line.
An automated cleaning device is shown in DE-PS 35 04 636. That device was the first to provide either the cleaning of the tap line to the tapping cock or, alternatively, the tap line to the keg. That device is also distinctly smaller, simpler and especially more beverage conforming than an earlier version shown in DE-OS 33 02 908, because it avoids bulky valve and check-valve configurations as well as horizontal, sharply angled beverage lines.
Although the device shown in DE-OS 33 02 908 is remotely operated via an electric motor, it requires too much room to be feasibly installed in common drafting or dispensing systems. This results in the remote operation feature generally not being used. Another key practical disadvantage of that device is the fact that the line leading to the keg has to be manually disassembled in usually a tight space, manually cleaned and manually reassembled whenever cleaning of that line is required, or whenever a new keg is connected.
Compared to that device, the unit shown in DE-PS 35 04 636 has the advantage of being of compact, space saving construction. Beverage carrying lines are exclusively ascending, straight and angle-free. It is especially important that it also allows the cleaning of the line to the keg without requiring it to be disassembled. That unit has, however, the disadvantage of having to move the sliding valve manually, i.e., not being remotely operable. In addition, the construction of the sliding valve is not optimized due to its square design and due to the switching device being located inside the sliding valve. The manufacturing of square fittings is also complex. Such square designs are also difficult to seal. Consequently, the sliding valve in the prior art is comparatively expensive.
An object of the present invention, therefor, is to design those cleaning devices more simply and more competitively, to make them universally applicable and to allow remote operation.
The foregoing objectives have been achieved by providing an automatic cleaning device in which the sliding valve is designed as a cylinder which can be turned around its longitudinal axis. A housing provides a single-ended sleeve bore for the sliding valve, which has a larger diameter than the sliding valve itself to function as a cylinder cavity. At the same end, the sliding valve is enlarged to function as a piston sliding in the cylinder cavity and to form a dual-acting hydraulic cylinder.
In addition, a retention hopper is connected to the housing containing elastic, porous cleaning balls to be inserted in the tap lines. The outside (OD) diameter of the balls is slightly larger than the inside (ID) diameter of the beverage carrying lines. At the connection point between the hopper and the housing, a spring loaded, annular sliding valve is designed as an outlet barrier for the cleaning balls. The housing itself contains a movable, sealed sliding valve equipped with a horizontal cross bore at one end and a specially formed cavity to accept the cleaning balls at the other end. In the tapping or dispensing position, the cross hole is in line with the sleeves of the two beverage carrying lines, while, at the same time, the cavity is in line with the outlet/annular sliding valve of the cleaning ball hopper. When moved into the cleaning position, the cavity is in line either with the sleeve of the tap line leading to the tapping cock or with the sleeve of the tap line leading to the keg, while, at the same time, a flow path through the housing and the sliding valve is opened from the sleeve of the pressurized water line to the cavity containing the cleaning ball.
Each cylinder can be filled with pressurized water controlled by a respective solenoid valve attached to the housing. A first solenoid valve is attached to a cover plate at the end of the housing. A second solenoid valve opens to a circular recess which is positioned at the end of the sleeve bore for the sliding valve. By opening the water-pressured, second solenoid valve, the piston and with it, the sliding valve, move into the cleaning position. The flow of the clean, pressurized water leads from the circular recess via the housing channels through the cross hole of the sliding valve, from here through another housing channel to a circular recess of the sliding valve, which is open to an endwardly enclosed, central pocket drilling of the sliding valve, which in turn is open to the cleaning ball cavity.
An enclosed end of the sliding valve incorporates a pilot pin which moves in a longitudinal groove of the housing. One half of the face of the housing is shortened, allowing the sliding valve and pilot pin to be turned by 180.degree. around their longitudinal axis using a tool, thus enabling the cleaning of the tap line to the keg, respectively, whenever the pilot pin is removed from the longitudinal groove, or the sliding valve is positioned in the drafting/dispensing position. The solenoid valves are electrically controlled from a switch located close to the tapping cock or, alternately, from a second switch attached to the housing.
In the presently preferred embodiment of the present invention, the cleaning device is equipped with a cylindrical sliding valve moving in a cylindrical bore of the housing. A square design of the movable and sealed components is thus avoided, ensuring reliable sealing as well as simple and cost efficient manufacturing.
A further simplification and thus an advantage of the present invention resides in the elimination of the switching device inside the sliding valve. Furthermore, the cleaning ball cavity is formed as a simple cross-pocket drilling of the longitudinally turnable valve. In this manner, the cleaning balls can alternately be inserted into either the tap line leading to the tapping cock or into the line leading to the keg.
It is especially advantageous that the dual-acting hydraulic cylinder for the valve operation is an integrated component of the sliding valve itself, thus allowing a remote operation by means of the incorporated solenoid valves and the electric switch at the tapping cock without the previously bulky construction and without impairing the quality of the beverage. Remote cleaning operation of the line leading to the keg from the tapping cock location, however, is blocked for safety reasons to avoid accidental water ingress and the insertion of a cleaning ball into the keg.
Since the cleaning of the line leading to the keg is only performed when changing a keg which requires the presence of a person at the location of the cleaning device, it is an advantage to require that the sliding valve be turned manually with a tool because this requirement promotes safety and eliminates excessive technical solutions.
It must be added that a remote operation for turning of the sliding valve is not beyond the scope of the present invention. Such a potential remote operation, however, requires additional technical efforts not only regarding the actual turning method, but, especially, concerning the prevention of pressurized water entering the keg.
Another major advantage of the cleaning device of the present invention is the use of pressurized water to operate the dual-acting hydraulic cylinder and, at the same time, to drive the cleaning ball and subsequently cleaning the tap lines whenever the device is switched to the cleaning position. Thus, there is a constant exchange of the pressure medium in the hydraulic cylinder assuring reliably that in no event, even in the case of a hypothetical malfunction, any foreign substance (e.g. hydraulic oils, etc.) could be introduced to the line system, since no such foreign substance, liquid or other medium is being used.
The present invention furthermore assures that the potential of stagnant water is eliminated, especially when the sliding valve is in the tapping position. Stagnant water could, even with the utmost hygienic precautions, become contaminated and result in promoting bacteria formation.
The present invention provides for solenoid valves and fittings to be designed and located in easily accessible, spacesaving positions. The adjustable pressure reduction valve permits operation with controlled pressures. Thus the cleaning device becomes independent of varying and fluctuating water pressures of the public utility system.
The present invention permits special treatment of the entire tapping/dispensing system, including the sliding valve, from time to time, e.g. for purposes of a complete disinfection treatment, in which case an appropriate chemical substance is, by remote control, injected into the system via the second solenoid valve.
The present invention promotes the design and construction of space saving blocks of sliding valves and enhances the operational reliability of the system. The pilot pin at the end of the sliding valve is located outside the groove in the housing whenever the unit is in tapping position. The sliding valve could, therefore, be accidentally twisted or could not have been moved back in the correct position after cleaning the tap line leading to the keg. In such a case, switching to the cleaning position from the remote location at the tapping cock, could result in accidental dilution of the beverage in the keg if the keg was already connected. Since the switch at the tapping cock is blocked in the present invention, such a mistake can not occur.
The present invention expands the universal applicability of the cleaning device for the following reasons. Many drafting/dispensing systems are equipped with so-called compensation tapping cocks. Such compensation tapping cocks are equipped with a central sliding piston at the cock connecting sleeve, allowing only an annular gap for the passage of the beverage. This central sliding piston is cone-shaped on the flow side. Opening of the cock generally results in a pressure decrease of the beverage in the cock and in the tap line. If the carbon dioxide pressure in the beverage is high, this pressure may be explosively released more or less far back into the line, depending on the individual properties of the beverage. In this case, the beverage may splash inconsistently and jerkily in a foamy consistency from the tapping cock.
Compensation tapping cocks create a relatively high, controlled flow resistance immediately in front of the cock by means of the central sliding piston, thus preventing undesirable pressure loss in the line in front of the cock. Therefore, it allows drafting of even highly sensitive beverages with a high gas pressure in a reliable and undisturbed fashion. Since the sliding piston reduces the ID-diameter of the tapping cock to the above-mentioned annular gap, the traditional cleaning ball cannot pass through. The utilization of the cleaning device would, therefore, only be possible if the compensation tapping cock would be unscrewed prior to the cleaning process and replaced afterwards. This cumbersome procedure would seriously jeopardize any advantages gained from the remote operated cleaning process.
The outward-transfer unit of the present invention for the cleaning balls avoids the above-mentioned. The tapping cock does not have to be unscrewed since the cleaning ball is automatically extracted. This is accomplished by a springloaded annular sliding valve. When the cleaning ball reaches the entry hole of the valve, it is pushed in front of the diameter-reduced through hole and seals its entry. This results in a pressurizing of the sleeve valve against the spring pressure towards the tapping cock. Once the opening for the cleaning ball with the sleeve valve has been moved far enough, i.e. across the vertical end of the tubular pipe, the pressurized water finds an egress and the flow or the pressure extracts the cleaning ball out underneath, while the safety pin prevents the cleaning ball from being pushed too far towards the tapping cock.